The present application relates to a liquid lens device utilizing an electrowetting phenomenon and a manufacturing method for such a liquid lens device.
In recent years, development has been advanced on an optical element utilizing an electrowetting phenomenon. The electrowetting phenomenon is a phenomenon such that when a voltage is applied between an electrode and a conductive liquid opposed to each other with an insulator interposed therebetween, the insulator is charged to cause a change in free energy of the interface between the insulator and the liquid, so that the shape (contact angle) of the surface of the liquid is changed.
Such an optical element can be applied to a variable focus lens, for example (see Japanese Patent Laid-Open No. 2007-225779 (paragraph [0039], FIG. 1), for example). In Japanese Patent Laid-Open No. 2007-225779, there is described an optical element having a lens surface formed by the interface between a conductive first liquid and an insulating second liquid stored in a liquid chamber. The liquid chamber is defined by a transparent substrate, a light transmitting container, and a sealing member interposed between the transparent substrate and the light transmitting container. The transparent substrate has an electrode layer covered with an insulating film. The container is provided with a rod electrode kept in contact with the first liquid. When a voltage is applied between the rod electrode and the electrode layer, an electrowetting phenomenon is exhibited to thereby change the shape of the lens surface.
In manufacturing the optical element as mentioned above, the liquid chamber is sufficiently sealed to avoid the leakage of the liquid. The sealing member is used as a component of the liquid chamber. After the liquid is charged into the liquid chamber, pressure is applied to the liquid chamber so as to compress the sealing member, so that the liquid chamber is sealed by an elastic force of the sealing member.